refactor!: claim references are claim:TAG

lode is renamed paperclaim. A claim reference is claim:TAG or
claim:host/TAG and a pin claim:TAG@hex6 (claimRef and claimPin in
common.schema.json, spec/18 §18.4, spec/02, spec/20); the eight-character
tags do not change. A project names its claim namespace as
claims.paperclaim, and the main example's targeted receipts take the
scope targeted:paperclaim. No old prefix or name is accepted.

paperspec build regenerated the fixtures and vectors: the claim link's and
the symbol's record IDs, the layer receipt, project.json, the two targeted
receipts and Ben's spot-check, the QA report, the inclusion proof, the log's
checkpoint and tiles, and the signature, spot-check, VRF and checkpoint
vectors. The walkthrough and examples quote the new receipt IDs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SarHTuHhV9cS85XWy2NrLJ

docs/walkthrough.md

@@ -143,11 +143,11 @@ It lifts a node to F3, the top fidelity level (F0 is one reading; F1, every doub
 One signature covers a Merkle tree, a hash over everything reviewed in a sitting, built as in RFC 6962 (a Request for Comments standard; replaced by [RFC 9162](https://www.rfc-editor.org/rfc/rfc9162), which defines the same tree).
 The receipts are in [`receipts.jsonl`](../fixtures/packages/hale2026harmonic-damb/receipts.jsonl), and the keys that signed them in [`roster.json`](../fixtures/packages/hale2026harmonic-damb/roster.json).
 
-- **Before the corrections**, `ana` had signed receipt `npc15pn6675z5` for three cells at revision 0.
+- **Before the corrections**, `ana` had signed receipt `vskq18t5sxydz` for three cells at revision 0.
   Two of them never changed, so the receipt still counts for them.
 For the corrected cell it no longer counts, because the cell's hash moved on.
-- After the corrections, `ana` signs `y2zw8ctg5s8dp` at F3 for 23 nodes: the cells of Table 1's three data rows (15), its four column headers, the equation, and three sentences (`ec5jc93`, `hca6dc5` and `rr20tev`, the one holding the equation).
-  `ben` spot-checks it with receipt `mg18668nzxvap`.
+- After the corrections, `ana` signs `fhhvg9qrzqp0n` at F3 for 23 nodes: the cells of Table 1's three data rows (15), its four column headers, the equation, and three sentences (`ec5jc93`, `hca6dc5` and `rr20tev`, the one holding the equation).
+  `ben` spot-checks it with receipt `ksx5sc327xp97`.
 His signature, made with his separate spot-check key `ben-spot`, picks 10 nodes nobody could have chosen, and he finds no errors.
 - `ana` signs `mvjmb94nz7rdh` for two sentences of section 1, including the new `a4jrz2t`.
 - `cara` signs `q465jpwz8afhe` for three sentences on page 2, then revokes it herself (`pcbhtpwvysgq6`) because she had compared them with the crops of another paper.
@@ -155,7 +155,7 @@ His signature, made with his separate spot-check key `ben-spot`, picks 10 nodes
 - `ana` signs `gx2s84z9jf9xv` for the figure's three caption sentences. `ben`'s spot-check `yt70fcc3qm0xb` finds a missing period in `caehhp6`, which suspends the receipt until she reviews the sitting again and signs a new one.
 
 The document's report, in [`document.json`](../fixtures/packages/hale2026harmonic-damb/document.json), counts the result over 45 leaves: 27 at F3, 13 at F2, 4 at F1 and 1 at F0.
-The 27 are the 23 nodes of `y2zw8ctg5s8dp`, the 2 of `mvjmb94nz7rdh`, and 2 of the 3 caption sentences.
+The 27 are the 23 nodes of `fhhvg9qrzqp0n`, the 2 of `mvjmb94nz7rdh`, and 2 of the 3 caption sentences.
 Those two still count because Ben's spot-check is itself a valid receipt, and he compared them with the page and found them right.
 The third, `caehhp6`, stays at F2: a spot-check never raises a node it found in error ([spec/08 §8.2](../spec/08-fidelity.md#82-levels)).